1. Field of the Invention
The present invention relates generally to a thin heat pipe structure and a manufacturing method thereof. The thin heat pipe structure includes a tubular body and a mesh body. Multiple intersecting channels are formed on an inner wall face of the tubular body to increase vapor/liquid diffusion efficiency. The mesh body is attached to the inner wall face of the tubular body. The thin heat pipe structure is able to transfer heat in both axial direction and radial direction.
2. Description of the Related Art
A heat pipe has heat conductivity several times to several tens times that of copper, aluminum or the like. Therefore, the heat pipe has excellent performance and serves as a cooling component applied to various electronic devices. As to the configuration, the conventional heat pipes can be classified into heat pipes in the form of circular tubes and heat pipes in the form of flat plates. For cooling an electronic component such as a CPU, preferably a flat-plate heat pipe is used in view of easy installation and larger contact area. To catch up the trend toward miniaturization of cooling mechanism, the heat pipe has become thinner and thinner in adaptation to the cooling mechanism.
The heat pipe is formed with an internal space as a flow path for the working fluid contained in the heat pipe. The working fluid is converted between liquid phase and vapor phase through evaporation and condensation and is transferable within the heat pipe for transferring heat. The heat pipe is formed with sealed voids in which the working fluid is contained. The working fluid is phase-changeable and transferable to transfer heat.
The heat pipe is used as a heat conduction member. The heat pipe is fitted through a radiating fin assembly. The working fluid with low boiling point is filled in the heat pipe. The working fluid absorbs heat from a heat-generating electronic component (at the evaporation end) and evaporates into vapor. The vapor goes to the radiating fin assembly and transfers the heat to the radiating fin assembly (at the condensation end). A cooling fan then carries away the heat to dissipate the heat generated by the electronic component.
The heat pipe is manufactured in such a manner that metal powder is filled into a hollow tubular body and sintered to form a capillary structure layer on the inner wall face of the tubular body. Then the tubular body is vacuumed and filled with the working fluid and then sealed. On the demand of the electronic equipment for slim configuration, the heat pipe must be made with a thin configuration.
A heat spreader works in the same principle as the heat pipe. The working fluid is converted between liquid phase and vapor phase through evaporation and condensation for transferring heat. The heat spreader is only different from the heat pipe in that the heat pipe mainly transfers heat in axial direction, while the heat spreader transfers heat face to face by large area. In adaptation to the current thin electronic equipment, the heat pipe or heat spreader must be manufactured with a thin configuration.
In the conventional technique, the heat pipe is pressed into a flat-plate form. Before flattening the heat pipe, the powder is first filled into the heat pipe and then sintered. Then the working fluid is filled into the heat pipe. Finally, the heat pipe is sealed. Alternatively, the tubular body of the heat pipe is first pressed and flattened and then the powder is filled into the tubular body and sintered. However, the internal chamber of the tubular body is extremely narrow. Therefore, it is quite hard to fill the powder into the tubular body. Moreover, the capillary structure in the heat pipe needs to provide capillary attraction for transferring the working fluid on one hand and support the tubular body on the other hand. The support effect is quite limited in such a narrow space.
Furthermore, the vapor passageways in the heat pipe are so narrow that an effective vapor/liquid circulation can be hardly achieved. Therefore, the conventional thin heat pipe and the manufacturing method thereof have many defects.
The most serious problem existing in the conventional technique is that although the thin heat pipe has larger heat absorption area and heat dissipation area, the heat pipe can only transfer heat in axial direction, while failing to transfer heat in radial direction. According to the above, the conventional technique has the following shortcomings:    1. It is hard to process and manufacture the thin heat pipe.    2. The capillary structure in the heat pipe is subject to damage.    3. The manufacturing cost is higher.    4. The conventional thin heat pipe cannot transfer heat in radial direction.